FIX + ENH: Fixed parameter for turning on/off time profiling. Fixed constructors and destructor in connection_m module. Added missing comments into connection_m module.

ENH: Building documentation added to the separate script build_docs.sh and removed from GitLab-CI testing.

ENH: Module 'connection_m' was cleaned up, so the dummy Neuron class was moved to the separate module 'neuron_dummy_m'.

FIX: Added script 'run_tests.sh for running all tests together and implemented this into .gitlab-ci.yml